adj.不可能的；難以置信的；想像不到的

It would be unthinkable to ask him to do that. 叫他做那件事是毫無(wú)可能的。

Only the effort of the group can make some unthinkable become thinkable. 大家的努力把一件不可能的事變成可能的。

That this project would achieve ultimate success was unthinkable at the time. 這個(gè)項(xiàng)目能獲得最后的成功在當(dāng)時(shí)對(duì)人們來(lái)說(shuō)是難以置信的。

The stars are an unthinkable distance from the earth. 恒星和地球的距離是難以想像的。